Take a look at this amazing joystick in development at Kelo University, the joystick uses your iPhone’s camera for the input rather than the touchscreen.
“There are small markers in this elastic device and the markers are detected by this built-in front-facing mobile phone camera. By tracking how the markers move as the elastic device deforms, this system enables a variety of inputs. Basically, the system’s precision depends on hardware factors, like the camera resolution and refresh rate.”
